Frost-Free Hose Bibb for Superinsulated House
Trevor_Lambert
| Posted in Mechanicals on
I can’t be the first person to face this problem, but it feels like it because I can’t see any product that addresses the problem. How the heck do you install a frost free hose bibb or sillcock without having a fitting inside the wall, when your wall is 21″ thick? The longest one I can find is something like 16″.
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http://www.woodfordmfg.com/woodford/Wall_Hydrant_Pages/model-24.html
We have 2 of the hot and cold Woodford Model 22 that were custom ordered for our 18" walls with 3/4" PEX connections.
I was so happy with them I installed another one in our trailer that has been used down to -5F.
I use one of the below linked valves inside the house. It allows me to isolate the hose bib and ensure the line is drained of water. I have a non frost free hose bib outside. This way the hose bib isn't flowing heat outside all winter long. I just open the valve when the outside temp gets high enough, and close it and briefly open vent and hose bib when the temp gets low. I leave the hose bib open but close the vent to make sure it's not an air leak.
https://www.homedepot.com/p/1-2-in-x-1-2-in-Brass-Full-Port-PEX-Ball-Valve-with-Adjustable-Drain-Forged-Lead-Free-405P012-NL/302620722
When I was looking for thermal bridging in my home I came upon the original frost free hose bib and I was shocked at how cold it was. I got rid of it as soon as I could.
Trevor,
You could probably use the type of method highlighted in this Matt Risinger video (at around 4:24). The PVC pipe and loop requires some room to install, but it should be doable if you are not too far along in the build process.
https://www.youtube.com/watch?v=JItfWP7Li-8
Trevor, you do not mention your state. If in MA, you'd have to select a sillcock product that is on the approved plumbing fixtures list or expect some additional redtape if your inspector is a stickler for the rules.
I'll re-open this to see if there has been any new ideas or products. For my house, I went with Calum's suggestion, but I'm not completely happy with it. The problem is it requires the homeowner to decide when to shut off the outdoor faucet for the winter. This requires you to be thinking about it, watching the weather forecast, and inevitably you either shut it off too late, or you shut it off and then have to turn it back on when the weather warms up again for a little while. There's a big overlap between the first freezing nights and when you want to stop using the outdoor water.
The Woodford model above, as far as I can tell, is not a frost free design.
I looked at the Aquor units, and have some reservations about those. The proprietary fittings, and the fact they are plastic is less than ideal. Seems like a very expensive product to be made out of plastic.
I've used assemblies like this before:
https://www.homedepot.com/p/Merrill-1-2-in-x-10-in-MIP-x-SWT-Frost-Proof-Ant-Siphon-Outdoor-Wall-Faucet-MAD10/308176718
The actual valve seat is located way back near the interior end of the long tube. There is a rod in the tube that connects the valve seat back to the outdoor handle. The way they work is to shut off the water inside, and the water in the tube drains out (you have to be sure to not leave anything connected to the outdoor part).
The only tricky part installing these sometimes is that the mounting bracket will force the tube to be pitched towards the outdoors to facilitate draining any remaining water inside the body of the unit. Sometimes this pitch makes the indoor end of the tube hit the subfloor depending on where the outdoor part needs to be mounted.
Bill
So that's the typical design that seems to be pretty ubiquitous. The problem is it would terminate somewhere inside the insulation in the wall. This may or may not be an issue when it comes to freeze protection, but it's definitely a concern to have a fitting inside the wall that would never again be accessible for inspection.
The threaded fittings are sized such that you can sweat a piece of copper pipe into them. That eliminates the "fitting in the wall" problem. You can also get these with a crimp-on PEX fitting, which, when installed with the copper crimp ring, should be pretty reliable long-term too.
If you get far enough into an insualted wall with the end of one of these, you should be OK. Remember that the temperature through the insulation gradually drops from the inside temperature to the outside temperature. Get the valve seat far enough into the wall that it stays in a region that is always above freezing and you should be OK.
Bill
Having seen a couple of PEX crimp rings leak, I'm pretty wary of them. Even a sweated joint in a concealed place doesn't make me feel great.
So let me do some back of the napkin math here. If I get a 12" freeze proof hydrant, which seems to be the longest widely stocked length: 12" minus 3/4" mounting plate, 5/16" siding, 1.5" rainscreen, 1/2" sheathing = 7.44" into the 16" insulated wall. That's 0.465 of the way to the inside. Worst case outside temperature is -30C, with the indoor temperature being probably around 16C right at the wall in the utility room. 0.465 of a 46deg differential is 21.4deg, putting the temperature at that point in the wall at about -8.5C. Admittedly that's not going to be a very common event. Looking at a more typical minimum of -20C, which will happen at least every couple of years, the temp at that point in the wall is -3.3C. I think I'd need a 16" freezeproof hydrant to feel adequately protected. In my original post I indicated I had seen those, but they must be somewhat rare since my cursory search today didn't turn any up.
You might try asking in a plumbing supply house. The commerical supply houses are typically more familiar with oddball items than the box stores are.
If you sweat a copper piece on, it will help conduct some heat to that fitting from the interior. Admittedly, the copper/brass pipe to the exterior will probably negate most of that though. You could sleeve the inner part of the assembly with something like 2" pipe to allow for some air movement, thus allowing the pipe to stay a bit warmer than it would if completely enclosed in insulation. How much difference that would really make, since the copper pipe is a huuuge thermal bridge anyway, I don't know -- I've never tried to measure anything like this.
You could always do this as a belt-and-suspenders job. Use the longest frost-roof spigot assembly you can find, AND use the drainable valve on the inside. If you do that, be sure to open and shut the outdoor valve after draining the indoor valve, since the pitched valve body on the frost-proof assembly will tend to still retain a small slug of water.
Bill
There's a Prier model that comes in up to 24" long, and they even say you can get units custom made in longer lengths.
https://www.prier.com/products/c-144/
I have the 24" one installed in an awkward spot where it had to go diagonally through some insulation, and it's worked well.
If you want to address the thermal bridging, you can also get one of those little insulated covers to go over the outside, which will help a bit.
https://www.zoro.com/frost-king-faucet-cover-plastic-and-foam-1-in-fc2/i/G5275891/feature-product
Another option is to install an access panel. You can put an insulation batt over the fitting and just remove it when you need to access it. Of course, you'll need to make an airtight box around the fittings or find a air tight panel.
Here is a 24" frost free sillcock:
https://www.amazon.com/Prier-C-144D24-Anti-Siphon-Outdoor-Hydrant/dp/B00HVLHQQM
Just about every PEX crimp and sweated joint in a typical house is in a concealed place.
What is more concerning to me is that sillcocks need to be replaced fairly regularly, the insides gum up and they start leaking. While they're designed to be serviced from the outside, it's not always possible to find service parts, and taking apart an old plumbing fitting is always a crapshoot. I would rather spend the $40 or so for a new sillcock than mess around with trying to take off a corroded threaded piece without snapping off the copper pipe on the inside.
So I like to install sillcocks with the assumption that they will be replaced regularly. My current favorite is to use a frost-free model, and position it so that the inside piping is accessible. I get a sillcock with a PEX connection, or if that's not available, a threaded connection and thread a PEX adapter onto it. I put about a foot of 1/2" PEX on the adapter. On the inside I run copper pipe up near the location, then a shutoff valve, a length of copper, and I use a Sharkbite to join the copper to the PEX.
Replacing the sillcock is a matter of turning off the water, taking out the two screws that hold the sillcock to the siding, and releasing the Sharkbite. Put the new fitting in, attach the Sharkbite and screw in the two screws.
This layout also makes the initial installation a lot easier, you do all the soldering out in the open a couple of feet away from the rim joist, instead of standing on a stepladder with your head jammed between the joists trying not to burn the house down or splatter molten solder on yourself.
I would be nervous reusing a sharkbit fitting too many times. I'm not a fan of them for permanent stuff anyway, but if you release and reattach them a bunch of times, I'm sure they'll eventually start to leak.
I hear you about molten solder. I have scar on my right hand from a blob of solder dripping onto me some years back. By the time you release what is happening, it's burned a hole through your skin. Not fun. Took a long time to heal too.
Bill
[replying to Bill's comment about the Sharkbite]
I expect a sillcock to last 5-10 years, so it's not going to be removed that often. But if you want to be sure you could replace the Sharkbite when you replace the sillcock. It's like a $5 item.
Trevor,
I have the Acquor bibbs and I like them. They are expensive, but they are well built and engineered. They also have a stainless steel cover option now - but that adds another $35. This is my 2nd winter with them and so far no problems.
Just for completeness, I'll note that a underground pipe below frost line to a freestanding yard hydrant is a solution that avoids having an above-grade penetration, puts the therm bridging below grade where temperature differences are small, and will leak into the ground, not the insulation, if something goes wrong.
Be careful install those. There are two types, one with a blowout and one that bleeds off the excess water into the ground. The kind that bleeds off excess water is disallowed by many health departments now for fear of contaminents entering the water supply.
Bill